Biophysical Society Thematic Meeting | Stockholm 2022

Physical and Quantitative Approaches to Overcome Antibiotic Resistance

Poster Abstracts

6-POS Board 6 E.COLI MEMBRANE STRUCTURE AND NANOSCALE DYNAMICS AT SUB INHIBITORY ANTIBIOTIC CONCENTRATIONS: CORRELATIONS TO EMERGENCE OF ANTIMICROBIAL RESISTANCE Anurag Chaudhury 1 ; Srividhya Parthasarathi 1 ; Ilanila I Ponmalar 1 ; Jaydeep K Basu 1 ; 1 Indian Institute of Science, Physics, Bengaluru, India Exposure of bacteria to sub lethal concentration of antibiotics gives rise to antimicrobial resistance. Various drugs target the bacterial membrane directly or indirectly, and understanding the bacterial membrane response thus becomes very important. Our Fluorescence Correlation Spectroscopy (FCS) results demonstrate the E.coli membrane getting loosely packed showing a higher diffusion co-efficient after adding antibiotics 1,2 . But growing E.coli in progressively increasing concentrations of antibiotics allows it to grow even at the minimal inhibitory concentration (MIC). Using super-resolution stimulated emission depletion (STED) nanoscopy coupled with FCS reveals the emergence of length scale dependent E.coli membrane dynamics for increasingly higher antibiotic concentrations starting from a sub-MIC value. It implies that the E.coli tries to adapt its membrane in order to grow even at the MIC value before finally becoming susceptible to concentration >1 MIC. Our AFM results show different patterns of roughness of the outer membrane during the process of the bacteria being allowed to grow at different antibiotic concentrations. These interesting results can be an important step in understanding how this gram-negative bacterium tries to develop antimicrobial resistance at short time scales upon exposure to antibiotics.[1] Ilanila Ilangumaran Ponmalar, Jitendriya Swain and Jaydeep K. Basu. Biomaterials Science 20, 2609-2617, 2022 (https://doi.org/10.1039/D2BM00037G)[2] Ponmalar, Ilanila Ilangumaran, Jitendriya Swain, and Jaydeep K. Basu. Biochimica et Biophysica Acta (BBA)-Biomembranes 1864, no. 8 (2022): 183935. * The authors thank the financial support from the Indian Institute of Science, (IISc), Bengaluru, through the Ministry of Human Resources Development (MHRD)-funded Institute of Eminence (IOE) project.

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